'Warspammers' are taking advantage of unprotected wireless LANs to send out millions of junk emails.

The proliferation of insecure corporate wireless networks is fuelling the growth of drive-by spamming, a security expert warned on Thursday.

Speaking at the First International Security Users Conference in London, Adrian Wright, managing director of Secoda Risk Management, warned that junk emailers are taking advantage of unprotected wireless local area networks to bombard email users with unsolicited and unwelcome messages.

"These people simply drive up to a building armed with their pornographic email, log into the insecure wireless network, send the message to 10 million email addresses and then just drive away," said Wright.